ns4.ndchost.com has no MX records.
Question and response
Question
dig ns4.ndchost.com. MX
Answer
The response has no answer records.
Authority
ndchost.com. 14440 SOA ns1.ndchost.com. webmaster.ndchost.com. 2026022206 3600 7200 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0